/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.state.api.utils;

import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.JobSubmissionResult;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.typeutils.TypeExtractor;
import org.apache.flink.client.ClientUtils;
import org.apache.flink.client.program.ClusterClient;
import org.apache.flink.runtime.jobgraph.JobGraph;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.source.FromElementsFunction;
import org.apache.flink.streaming.api.functions.source.SourceFunction;
import org.apache.flink.test.util.AbstractTestBase;
import org.apache.flink.util.AbstractID;

import java.io.IOException;
import java.util.Collection;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;

/**
 * A test base that includes utilities for taking a savepoint.
 */
public abstract class SavepointTestBase extends AbstractTestBase {

	public <T> String takeSavepoint(Collection<T> data, Function<SourceFunction<T>, StreamExecutionEnvironment> jobGraphFactory) throws Exception {

		StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
		env.getConfig().disableClosureCleaner();

		WaitingSource<T> waitingSource = createSource(data);

		JobGraph jobGraph = jobGraphFactory.apply(waitingSource).getStreamGraph().getJobGraph();
		JobID jobId = jobGraph.getJobID();

		ClusterClient<?> client = miniClusterResource.getClusterClient();

		try {
			JobSubmissionResult result = ClientUtils.submitJob(client, jobGraph);

			return CompletableFuture
				.runAsync(waitingSource::awaitSource)
				.thenCompose(ignore -> triggerSavepoint(client, result.getJobID()))
				.get(5, TimeUnit.MINUTES);
		} catch (Exception e) {
			throw new RuntimeException("Failed to take savepoint", e);
		} finally {
			client.cancel(jobId);
		}
	}

	private <T> WaitingSource<T> createSource(Collection<T> data) throws Exception {
		T first = data.iterator().next();
		if (first == null) {
			throw new IllegalArgumentException("Collection must not contain null elements");
		}

		TypeInformation<T> typeInfo = TypeExtractor.getForObject(first);
		SourceFunction<T> inner = new FromElementsFunction<>(typeInfo.createSerializer(new ExecutionConfig()), data);
		return new WaitingSource<>(inner, typeInfo);
	}

	private CompletableFuture<String> triggerSavepoint(ClusterClient<?> client, JobID jobID) throws RuntimeException {
		try {
			String dirPath = getTempDirPath(new AbstractID().toHexString());
			return client.triggerSavepoint(jobID, dirPath);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}
}
